If the 2C global warming limit is inaccurate then the amount of available carbon left to burn could be much less than thought.
Photograph: Enrique de la Osa/Reuters

13 months and counting

Measurement can be simply a matter of getting things to fit– or a matter of life and death. By confusing different scales and units, a friend once nearly ordered a Venetian blind that would have been three metres wide and only three inches deep.

Rather more seriously, in 1999 Nasa’s $300m (£200m) programme to learn from the climate of Mars was wrecked when its Climate Orbiter vanished as it approached the planet. It later transpired that the Orbiter’s entry angle for its ‘orbital insertion’ was incorrect. At the planning stage the best brains in astronautics and space engineering had mixed up metric and imperial measurements. That was bad enough, but surely today some of our cleverest people wouldn’t make similar, basic errors in measuring the emissions and resources needed to preserve the climate on which we depend, would they?

In the last month both have been questioned. Kevin Anderson of the Tyndall Centre for Climate Change Research writes that the generally accepted target for staying below 2C is, in fact, way off the mark. Similarly, an inquiry into the design of a sustainable financial system by the United Nations environment programme (Unep) reveals a multi-trillion dollar shortfall in the investment needed to finance the new Sustainable Development Goals, which include internationally agreed climate action.

Could the 2C climate target be completely wrong?

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The stakes couldn’t be higher, withthe global average surface temperature this year set to breach 1C above the average for the years 1850-1900, the pre industrial time before most human emissions from fossil fuel-burning occurred.

Based on the climate models used by the Intergovernmental Panel on Climate Change (IPCC), current national pledges to reduce emissions and hold temperature rises below 2C, are already seen as inadequate. But Anderson argues that even this dramatically understates how far short of the target we really are, and that instead of relying on comfortingly ‘evolutionary’ policies, a revolutionary approach is needed.

The problem, explained by Anderson in a comment for the journal Nature Geoscience, is one of simple arithmetic and assumptions that are either impossible or implausible. Multiple scenarios inform how much carbon the IPCC thinks it will still be safe to burn and have a chance of not crossing the 2C line. But, writes Anderson, all the 400 IPCC scenarios that give a 50% or better chance of avoiding 2C “assume either an ability to travel back in time or the successful and large-scale uptake of speculative negative emission technologies”. Some of the scenarios assume that global emissions have already peaked, when they haven’t, and others assume the success of large scale, unproven geo-engineering. Some make both assumptions.

A more realistic assessment dramatically reduces the amount of ‘burnable’ carbon. An original IPCC carbon budget of 1,000 gigatonnes of carbon dioxide to last from 2011 – 2100 (giving a two-thirds chance of keeping below 2C) becomes just 470 gigatonnes to last from 2020 - 2100. You could say that official targets appear to be missing their angle for ‘orbital insertion’ by more than enough to crash the climate.

The failure of the broader expert and scientific community to be more explicit about the nature and implications of successful climate action suggests that “vested interests and the economic hegemony may be preventing scientific openness and freedom of expression”, says Anderson.

The other great miscalculation concerns the resources committed to action against the likely scale of investment needed. Climate targets can only be pursued in the context of broader economic development strategies and overarching these are the new, universal Sustainable Development Goals. The new Unep research on a sustainable financial system notes that natural capital is declining in 116 of 140 countries included in the overview. It estimates the need to cut $6tn worth of investment in highly polluting energy systems, while hugely increasing investment elsewhere.

For clean energy, water, sanitation, farming and infrastructure in developing countries there is a current funding shortfall of $2.5tn annually, while the investment gap for major economies is set to hit $10tn annually by 2020. These sums seem vast but institutional investors such as pension funds manage over $100tn in financial assets, banking around $140tn, and trillions more move around bond and equity markets. Plus, when needed, the public sphere can create trillions of new money, as it did to bail out the banks, which can lever disproportionately still larger sums of investment from other sources.

We need to get the right measure of the problem, in terms of both emissions and resources. Doing so will be the difference between producing policies that save lives and stabilise the climate, or ones that aren’t fit for purpose and merely flutter in the wind of a world warming out of control.